The present invention relates to self-locking cattle stanchions of the type having a plurality of individual stations into which animals automatically lock themselves. Such stanchions are illustrated in U.S. Pat. Nos. 4,037,566 and 4,055,149; German publications Nos. 2,316,736 and 2,446,026; and French published application No. 2,242,929. As shown in these patents, the stanchions generally include a structure having a plurality of pairs of generally vertical standards defining the individual stations. One standard of each pair is pivotally mounted so that it swings away from the other stationary standard to permit the animal's head ingress or egress to the station. As the animal inserts its head between the two standards, movement of the animal's head trips the pivot standard to the closed position locking the animal therein.
As the state of the art has progressed various types of locking and release mechanisms have been utilized to control the ingress and egress of cattle from the stanchion. Most of these devices have been complex and expensive to produce, in addition to being expensive and time consuming to maintain because of the many components. Further, the locking mechanisms known before include a swivel element pivotally attached to the upper end of the swinging standard which slides along a track and generally drops into a slot or behind an abutment. Maintenance problems can be significant in instances where the stanchions include so many movable and cooperating components. Because of exposure to dampness in dairy barns, feeding shelters, etc., if the components are not kept clean and well-oiled there is increased likelihood of rust and consequent failure and damage. In the devices of the prior art, where rusting occurs easy movement of the swivel element and thus the entire swinging standard is curtailed making it difficult or frustrating for the animals to reach their food. It is also obviously more expensive to maintain such complex structures, especially where those locking components move back and forth continuously with the standard.
Mention should also be made of the fact that the swinging standards of the prior art are generally straight and pivoted at the center. So arranged the cow's head engages the lower inclined portion of the standard as its head is lowered for feeding to close the standard. Upon unlocking of the swinging standard, however, a force against the upper portion (above the pivot point) is necessary to open the station. This is not always reliable, particularly if the cow is pushing against the standard below the pivot point.
Other problems with the prior art self-locking mechanisms include ease of control in locking and releasing mechanism. These mechanisms have also generally been more complex than necessary to function. Many of them employ spring or other types of biasing means, complex pivot elements, all of which make the operation susceptible to jamming after continued use and exposure to moisture and dirt.
The present invention, however, is directed to an improved cattle stanchion and simplified locking/release apparatus having a minimal number of components and potential friction induced jams. Thus, maintenance is considerably less time-consuming and expensive, in addition to the more economical initial production costs.
A preferred embodiment of the present invention includes a stanchion structure generally comprised of top and bottom, horizontally extending rails and a plurality of substantially vertical rods or posts extending therebetween in pairs to define the individual cattle stations. In each pair of standards, a first one is stationary and a second one is generally J-shaped and pivotally connected at its lower end to the bottom rail. The stationary standard and the adjacent, horizontally spaced, pivoting standard define an individual cattle station. The two standards cooperate such that the pivoting standard is in a first access position tilted away from the stationary standard to widen the opening sufficient to permit an animal to move its head therebetween. After the animal is positioned and lowers its head to eat, the movement of its head will tilt the pivoting standard toward the stationary standard to narrow the opening, automatically lock into place, and thus prevent the animal moving out of the station.
The swingable standard as noted above is preferably J-shaped, and pivotally attached at its lower end to the bottom rail. This shape of the swinging standard effects a counterbalance on the longer leg to normally urge the swinging standard toward an open position. The upper end moves back and forth within a horizontal trackway formed between two walls of the top rail. The track has at least an open bottom with sidewalls formed by the components of the top rail. A locking bail is pivotally mounted at one end along the upper edges of the sidewalls of the track and includes an inclined tongue portion extending down between the walls of the upper rail in operative locking relationship to the upper end of each swinging standard. The tongue allows movement of the upper end of the swingable standard in one direction, but not the other; e.g. as a ratchet mechanism operates.
A master control rod includes means to selectively support the free end of the locking bails of all stations out of the trackway in a deactivated position when it is desirable to open the stations or when it is undesirable for the cattle to lock themselves in their respective stations. When it is desirable for the cattle to lock themselves in, the control rod is moved horizontally to a second position whereby the bails are allowed to drop by gravity to an activated position within the track. As the cattle move into the stations and lower their heads, the motion of the head and neck will cause the swingable standard to tilt inwardly toward the stationary standard with the upper end of the swingable standard passing the tongue portions of the locking bail so that the standard cannot move back to its open position.
The master control rod includes a lock disengaging means in the form of a plate movable therewith from a position removed from said locking bail to a position underneath and supporting the tongue of the locking bail above the aforementioned track. In use, the pivoting standard would normally be in its freely moving mode with the control rod in a first, deactivated position whereby the locking bail is supported above the trackway. When it is time for the cattle to enter the stanchion the control rod is moved into the second, activated position wherein the locking bails are permitted to drop into the trackway a depth sufficient to lie in the path of the upper end of the swingable standard when it is moved toward the closed position by the cattle. Because the locking bails are freely pivoted in either vertical direction, and the tongue is inclined away from the path of movement at this time, they will ratchet upwardly out of the trackway when the pivot standard passes thereunder, then will drop back into the track to engage the upper end of the stanchion and block its movement in the opposite direction should the animal attempt to withdraw its head from the station.
Thus applicant has invented a cattle stanchion with a unique self-locking mechanism having a minimum number of moving elements, with each of the primary elements other than the control rod, being operative on a simple pivot means. All frictional engagement of relatively moving parts is very loose. The control rod moves horizontally adjacent the top rail by means of a simple handle and is held in place on the rail by a plurality of spaced, metal loops which are welded or otherwise secured to one side of the top rail to act as a channel for the control rod.
Thus, necessary maintenance is kept to a minimum and routinely involves merely keeping the control rod and pivot points relatively clear and lubricated. Should one of the pivot connections fail, repair would generally require only the replacement of a standard pivot pin. The stanchion structure is preferably of a tubular metal material but other materials are possible.
It is therefore an object of the present invention to provide a more reliable self-locking cattle stanchion having a minimum number of movable cooperative elements such that production and maintenance costs are as economical as possible. It is further desired that the operation of the stanchion be simplified and easily controlled by one operator.